Generate in build.rs

Two APIs — pick whichever fits your project:

generate_to_dir writes generated codecs to a directory you control (prefer src/generated/ for IDE go-to-definition). The feature-tour sample uses this pattern:

#![allow(unused)]
fn main() {
    let generated_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("src/generated");
    let config = ergo_sbe::GenerationConfig::new("feature_tour")
        .with_domain_objects(ergo_sbe::DomainVarData::Strings)
        .with_domain_type(
            ergo_sbe::ConversionSelector::named_type("BooleanType"),
            "bool",
        )
        .with_domain_type(
            ergo_sbe::ConversionSelector::semantic_type("UTCTimestamp"),
            "chrono::DateTime<chrono::Utc>",
        )
        .with_conversion(ergo_sbe::ConversionSelector::named_type("Decimal"))
        // Same shape as Decimal, but the app supplies the impl itself — see
        // demo_domain_type_manual_impl in src/lib.rs.
        .with_manual_domain_type(
            ergo_sbe::ConversionSelector::named_type("ManualDecimal"),
            "rust_decimal::Decimal",
        );

    ergo_sbe::generate_to_dir("schemas/feature-tour.xml", config, &generated_dir)?;
}

generate_to_out_dir writes to Cargo’s $OUT_DIR and emits cargo::rerun-if-changed automatically. Use with include!(concat!(env!("OUT_DIR"), …)) — simpler, but rust-analyzer usually cannot jump into generated code.

Schema from a string / include_str!: generate_str_to_out_dir.

Need multi-schema or custom output paths? Use the lower-level parse_file + Generator API (same steps the helper runs). For shared types across schemas, see Multi-Schema Patterns below.